The efficiency of decontamination of aflatoxin residues in poultry feeds through exposure to sunlight (solar radiation), γ-radiation ( 60 Co), and microwave heating were investigated in artificially contaminated feed samples. Photodegradation of aflatoxin by sunlight has been found to cause a significant (P < 0.05) decrease in both B1 and the total aflatoxins. Moreover, the degrees of aflatoxins were dependent on exposure time. Both aflatoxin B1 and total aflatoxins were decreased when feed samples exposed to sunlight by 42.3, 39.9, 75.5, and 65.9% for 3 and 30 h of direct sunlight of the treatment T1, whereas feed samples subjected to γ-irradiation and microwave heating caused a significant (P < 0.05) decrease in aflatoxin B1 contents by 42.7 and 32.3% for γ-irradiation and microwave heating (T3 of 25 kGy and 10 min of microwave heating), respectively. Therefore, the solar radiation was more effective in aflatoxin B1 reduction when compared with γ-irradiation and microwave heating.

Reported here are the effects of added formic acid on inhibitory effect of Salmonella gallinarum in poultry feed. Two experiments were conducted to investigate the viability of S. gallinarum and pH of poultry feed using different dietary formic acid levels (0.0, 0.5, 1.0 and 1.5%) on inhibitory effect of S. gallinarum in broiler feed. Experiment one was conducted to investigate the viability of S. gallinarum and pH of artificially contaminated diet at 0, 1, 3, 5 and 7 days after treatment in vitro. Formic acid showed a significant (p<0.05) reduction in the viability for all treatments with time after treatment. Various formic acid levels in vitro showed a reduction in the pH of the diet depending upon the concentration of treated acid, and the diet remained acidic below the growth range of S. gallinarum. This meant that the bacterial cells were exposed to stressful conditions that made them unable to grow. Experiment two was conducted to find out the effect of dietary formic acid levels on S. gallinarum colonization and pH in the contents of crop, small intestine, large intestine and ceca and mortality rate of broiler chicks at 7, 14 and 21 days of age when fed artificially contaminated diet with S. gallinarum. The numbers of S. gallinarum re-isolated from all treated groups except in groups treated with 0.5% formic acid, decreased significantly (p<0.05) compared with the control group. The treatment significantly (p<0.05) lowered the pH of the crop, small intestine, large intestine and ceca contents in all groups except the groups treated with 0.5% formic acid compared with the control. All treated groups showed a significant (p<0.05) reduction in overall mortality rate during the experimental period (3 to 21 days) compared with the control. The results indicate that addition of formic acid in a total concentration of 1.5% to the diet of newly hatched broiler chicks significantly decreases the contamination of diet with S. gallinarum.

This investigation was conducted to study the effect of dietary formic acid (FA) and propionic acid (PA) mixture on inhibitory effect of Salmonella pullorum in layer chicks. Nine equal groups of 1-day-old layer chicks, in addition to positive and negative controls, were fed on day 3 of age with acid-treated feed containing mixture of both acids at concentrations, from 0.5 to 1.5%. Positive and negative controls were fed untreated feed. All groups except the negative control were challenged orally on day 3 with 104 CFU/ml/bird S. pullorum. Cloacal swabs were taken at three successive days and at 7, 14 and 21 days of challenge. After 1, 2 and 3 weeks after challenge, four chicks from each group were killed, and crop and caecal contents were examined for S. pullorum and pH. The numbers of S. pullorum re-isolation from all treated groups, 'except groups treated with mixture of 0.5% and 0.5%, 1% and 0.5% as well as 0.5% and 1% FA and PA', decreased significantly (P < 0.05) compared with the positive control. The mortality rates of all treated groups except the group treated with 0.5% FA and 0.5% PA decreased significantly (P < 0.05) compared with the positive control. The treatment significantly (P < 0.05) lowered the pH of the crop and caecal contents in all groups except the group treated with 0.5% FA and 0.5% PA compared with the control. Also, the treatment significantly (P < 0.05) lowered the pH of the crop and caecal contents in all groups after 3 weeks of treatment compared with the first and second weeks. The treatments significantly (P < 0.05) lowered the frequency of S. pullorum recovery from crop and caecal contents in six groups treated with 1.5 and 0.5, 1 and 1, 1.5 and 1, 0.5 and 1.5, 1 and 1.5, 1.5% and 1.5% FA and PA, respectively. These results indicate that addition of FA and PA mixture in a total concentration of 2% or more to the diet of newly hatched infected layer chicks significantly decreases the crop and caecal colonization by S. pullorum and significantly decreases S. pullorum faecal excretion and reduced the chick mortality rate.

This experiment was conducted to study the effect of dietary propionic acid on inhibitory effect of Salmonella gallinarum. Day-old 144 broiler chicks were randomly distributed into four dietary treatments, three replicates per treatment. The four dietary treatments consisted of 0.0, 0.6, 1.2, and 1.8% dietary propionic acid. Chicks were challenged orally on three days of age with 10 6 cfu Salmonella gallinarum. Sample of crop and cecal contents were obtained on Days 1, 8 and 15 post-inoculation. The pH of crop contents decreased significantly (p<0.01) for groups of chicks provided 1.2 and 1.8% propionic acid in the diet as compared with those provided 0.6% propionic acid and control group. The pH of cecal contents decreased significantly (p<0.01) for groups of chicks provided with 0.6, 1.2 and 1.8% of propionic acid as compared with control group. The number of Salmonella gallinarum positive culture in the crop and ceca of chicks, decreased significantly (p<0.01) from the groups provided with 0.6, 1.2 and 1.8% of propionic acid in the diet at day 1, 8 and 15 post-inoculation. The addition of 1.8% propionic acid in the diet provided a high level of protection against colonization than did 0.6 and 1.2%. These results indicate that the addition of propionic acid in a concentration of 1.2 or more to the diet of newly hatched chicks significantly decreases crop and cecal colonization by Salmonella gallinarum.

This investigation was conducted to study the effect of dietary formic acid (FA) and propionic acid (PA) mixture on inhibitory effect of Salmonella pullorum in layer chicks. Nine groups of one day-old layer chicks in addition to positive and negative controls, were fed with acids treated feed containing mixture of different acids concentrations, from 0.5% and 0.5% up to 1.5% and 1.5% FA and PA, respectively. Positive and negative controls were fed untreated feed. Groups except the negative control were challenged orally on day three with 10 4 cfu/ml S. pullorum. Cloacal swabs were taken at three successive days and at 7, 14 and 21 days of challenge. After 1, 2 and 3 weeks after challenge, 4 chicks from each group were sacrificed and crop and cecal contents were examined for S. pullorum and pH. The numbers of S. pullorum positive culture from the excretion of all treated groups except groups treated with mixture of 0.5% and 0.5%, 1% and 0.5%, 0.5% and 1% FA and PA decreased significantly (p<0.05) as compared with the positive control. The mortality rates of all treated groups except the group treated with 0.5% FA and 0.5% PA were decreased significantly (p<0.05) as compared with the positive control. The treatment significantly (p<0.05) lowered the pH of the crop and cecal contents in all groups except the group treated with 0.5% FA and 0.5% PA as compared with the control. Also, the treatment significantly (p<0.05) lowered the pH of the crop and cecal contents in all groups after three weeks of treatment compared to the first and second weeks. The treatments significantly (p<0.05) lowered the frequency of S. pullorum recovery from crop and cecal contents in six groups treated with 1.5 and 0.5, 1 and 1, 1.5 and 1, 0.5 and 1.5, 1 and 1.5, 1.5% and 1.5% FA and PA respectively. These results indicate that addition of FA and PA mixture in a total concentration of 2 % or more to the diet of newly hatched infected layer chicks significantly decreases the crop and cecal colonization by S. pullorum and significantly decreases S. pullorum fecal excretion and reduced the chick mortality rate.